U.S. Pat. No. 4,688,388, assigned to the assignee hereof, discloses apparatus for service and recharge of refrigeration equipment, with particular application to automotive air conditioning equipment. A vacuum pump and a refrigerant charge container are housed within a wheel-mounted cabinet and configured for selective connection to refrigeration equipment under service, by hoses and electrically operated solenoid valves carried by the cabinet. The refrigerant container is carried by a scale that provides electrical output signals as a function of weight of refrigerant remaining in the container. A microprocessor-based controller receives the scale signals and control signals from an operator panel for automatically cycling through vacuum and refrigerant charge stages in a programmed mode of operation. The microprocessor-based controller includes an alphanumeric keypad for operator programming of vacuum time and refrigerant charge quantities in a program mode of operation, an alphanumeric digital display for indicating vacuum time and charge quantities, and facility for self- or operator- implemented diagnostics. Operating conditions and stages are displayed to the operator.
U.S. Pat. No. 4,768,347, also assigned to the assignee hereof, discloses a refrigerant recovery system that includes a compressor having an input coupled through an evaporator and through a solenoid valve to the refrigeration equipment from which refrigerant is to be withdrawn, and an output coupled through a condenser to a refrigerant storage container or tank. The evaporator and condenser are contained within a closed cylindrical canister for heat exchange and oil separation, the canister having an oil drain in the bottom. The refrigerant storage container is carried by a scale having a limit switch coupled to the control electronics to prevent or terminate further refrigerant recovery when the container is full. The scale comprises a platform pivotally mounted by a hinge pin to a wheeled cart that also carries the evaporator/condenser unit, compressor, control electronics, and associated valves and hoses.
U.S. application Ser. No. 157,579, filed Feb. 19, 1988 and assigned to the assignee hereof, discloses systems for recovering, purifying and recharging refrigerant in which, during a purification cycle, refrigerant is circulated from the refrigerant storage container in a closed path through a circulation valve and a filter for removing water and other contaminants, and then returned to the container. U.S. application Ser. No. 263,887, filed Oct. 28, 1988 and also assigned to the assignee hereof, discloses a refrigerant recovery system that includes a refrigerant storage container, refrigeration circuitry for withdrawing refrigerant from equipment under service and feeding such refrigerant to the container for storage, and a scale supporting the container for sensing impending overfill of the container. The scale includes a beam horizontally rigidly cantilevered from a base. A switch is positioned adjacent to the cantilever-remote end of the beam, and is responsive to deflection of the beam to indicate impending overfill of the container and prevent or terminate operation or the refrigerant recovery system.
A problem with refrigeration service devices of the subject character, including the devices disclosed in the above-noted patents and applications, lies in potential for escape of refrigerant to the atmosphere when the devices are connected to and disconnected from the equipment under service and each other. Thus, conventional practice typically requires "cracking" of interconnections to purge air from the service system when the devices are initially connected to the equipment for service, with consequent loss of refrigerant during the purging operation. There is also potential for substantial loss of refrigerant in the interconnection hoses and manifold when the devices are disconnected from the equipment as part of or following the service operation. Thus, although the refrigerant recovery and/or purification systems disclosed in the noted patents and applications recover and recycle a major portion of the refrigerant in equipment under service, there remains the problem of leakage and escape of refrigerant during the connection and disconnection operations. Many scientists contend that release of halogen refrigerants into the atmosphere deleteriously affects the ozone layer that surrounds and protects the earth from ultraviolet solar radiation. Recent international discussions and treaties, coupled with related regulations and legislation, have further increased interest in preventing such refrigerant leakage.
A general object of the present invention, therefore, is to provide a system for servicing refrigeration equipment that reduces or eliminates leakage and escape of refrigerant to the atmosphere during the process of connecting and disconnecting the service devices to and from the equipment under service. Another and more specific object of the invention is to provide a coupling that is construction for rapid connection and disconnection to and from equipment under service, that is particularly well adapted for use in conjunction with service of refrigeration equipment having service fittings of predetermined industry-standard contour, and that is economical to manufacture and reliable over an extended operating lifetime. Yet another object of the invention is to provide a service manifold assembly having refrigerant conduits and quick-disconnect couplings of the subject character that is specifically adapted for use by service operators who already have a number of service devices, who do not wish to purchases redundant equipment, and yet who desire to prevent leakage of refrigerant into the atmosphere.